1. Field of the Invention
This invention generally relates to functionalized polymers (e.g., chemically inert polymers) for coating or forming an implantable device.
2. Description of the Background
Inert polymers such as fluoropolymers and others have been used to form coatings on an implantable device or an implantable device. While some of these polymers can have good properties, e.g., the ability to control drug release rate, good biocompatibility, good mechanical integrity, inertness, or processability, it is often desirable to modify these polymers to alter their drug permeability or to functionalize them to attach moieties for pro-healing, thromboresistance, or biobeneficiality. Generally, a coating or surface is considered biobeneficial when it confers some biological benefit, i.e. thromboresistance, non-fouling, anti-inflammatory, or platelet resistant, without the release of a pharmacologically active agent.
However, due to these polymers' inertness, it is relatively difficult to modify the polymers. For example, chemical functionalization of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is possible but requires harsh conditions, e.g., heating the polymer in KOH/MeOH at 60° C. for 4 hours to introduce unsaturation followed by treatment with 98% sulfuric acid at 80° C. for 48 hours to oxidize the unsaturation to introduce hydroxyl and carboxyl groups (e.g., Bottino, A., et al., J. Membrane Sci., 166:23-29 (2000)).
Therefore, there is a need for functionalizing inert polymers under relatively benign conditions. The embodiments described below address such problems and needs.